Network services are often inserted into a network. The network services may be services not included in the standard IP protocol. For example, the network services may include, but are not limited to, load balancing or application delivery services. The network services may be performed by one or more service appliances, which may be server blades integrated into network elements (e.g., switches, routers, etc.) or external appliances. The provision of network services typically necessitates manual configuration of network elements and network nodes (e.g., servers).
For example, when providing load balancing or application delivery services, a client device sends a request (e.g., one or more packets) that is intercepted by a service application running on one or more of the service appliances. The service application is configured to select a server among a group of servers to fulfill the request and to transmit the request to the selected server. To ensure that return packets (e.g., packets flowing from the selected server to the client device) are transmitted via the service application, one of the following steps is taken: (1) routing/redirection rules are setup on each of the network elements, (2) the service appliance is configured to perform source network address translation (NAT), or (3) the service appliance is setup as a gateway on each of the servers.
The existing solutions, however, have several drawbacks. For example, routing/redirection rules are typically manually configured in the network elements. Manually configuring routing/redirection rules can be a cumbersome, time-intensive operation, particularly in complex network environments where thousands servers (e.g., 16,000, for example) can be connected to each network element. Additionally, changes in state, availability and mobility of the servers and virtual IP addresses often require configuration updates in the network elements and/or the servers. Further, source NAT is an unacceptable deployment in network environments where the client's IP address is required to be known to and/or recorded by the servers (e.g., financial services networks).